Production of metals and their alloys

ABSTRACT

Methods for manufacturing titanium and zirconium alloys, particularly including such alloys in powder form by continuous vapor phase chloroaluminothermic reduction.

[0001] The U.S. Government may have rights in certain of the titaniumaspects of the invention under SBIR Contract No. DASG60-00M-0087 withthe Ballistic Missile Defense Organization. This application is based onU.S. Provisional Applications 60/169,580 filed Dec. 8, 1999 entitled“Production of Titanium and Intermetallic Alloys” and 60/190,981 filedMar. 21, 2000 entitled “Zirconium Production by Reactive Distillation”.

FIELD OF THE INVENTION

[0002] The present invention is directed to the production of metals andtheir alloys, particularly including refractory metallic alloys such astitanium and zirconium aluminides and amorphous metals.

BACKGROUND OF THE INVENTION

[0003] As the fourth-most plentiful metal in the earth's crust, titaniumis relatively abundant in nature (e.g., as rutile-TiO₂ andilmenite-FeTiO₃, and has highly useful properties. However, thisrefractory metal is unfortunately relatively expensive to extract andreduce from its ores, and difficult to fabricate into useful products inview of its high melting point, sometimes requiring use of film orpowder metallurgy techniques such as hot isostatic processing of apowdered or thin film form. It is difficult to purify, and even moreexpensive to prepare in powder form suitable for advanced powdermetallurgical manufacturing processes.

[0004] Titanium is conventionally produced by reduction of titaniumtetrachloride with magnesium metal in a steel batch retort (the “Krollprocess”). A significant part of the high cost of titanium as a resultof the inefficiency and batch nature of the Kroll process which iscurrently used for its manufacture. This process produces crude titanium“sponge” which may be intimately contaminated with magnesium chlorideand titanium subchlorides, as well as impurities in the magnesiumreducing agent. The crude titanium “sponge” which the Kroll processproduces, requires costly vacuum arc refining to produce refinedtitanium ingots which are suitable for manufacturing use. Subsequentgrinding and/or plasma particulation of the refined ingot to produceuniform powders for powder metallurgy and composite manufacture is alsorelatively expensive.

[0005] Titanium forms alloys and intermetallic compounds of significanttechnical importance. Titanium alloys, and especially titaniumaluminides, are important, but costly, materials for aerospacecomponents for propulsion and power. The relatively low density oftitanium and titanium alloys, combined with their high specificstiffness, high strength, high corrosion resistance and relativetoughness, are particularly desirable in aerospace systems. Theefficiency of high-performance propulsion systems and turbines islimited by the high temperature capabilities of materials used forengine components. Relatively lightweight gamma-TiAl based intermetallicalloys have desirable strength to weight and other properties,particularly in comparison with the heavier titanium and nickel-basealloys currently used in combustion and compressor sections of engines.A two-phase (TiAl+Ti₃Al), structure distributed as fine or coarselamellar microstructures including the α2 (Ti3Al), orthorhombic(Ti₂AlNb) and γ (TiAl) classes of alloys may be particularly optimal forsome applications. More sophisticated titanium and TiAl reinforcedcomposite aerospace components, such as advanced SiC-fiber-reinforcedtitanium alloy aeroengine and structural components, are underdevelopment in many countries (including the U.S., France, the U.K. andChina). Such advanced composites utilize expensive Ti or TiAl powdersand/or foils in their manufacture. [see, e.g., Z. X. Guo, “Towards CostEffective Manufacturing Of Ti/SiC Fibre Composites And Components”,Materials Science and Technology, Vol. 14, pp. 864-872 (1998)].

[0006] Zirconium and its alloys are of particular use to the nuclearpower industry, and chemical and materials industries, and for amorphousmetal compositions. The corrosion resistance, mechanical properties andneutron transparency of Zirconium, make Zirconium-based alloys importantmaterials for containing or alloying with uranium fuel, and for theconstruction of critical components of nuclear reactors. Zirconium alsohas a wide variety of other uses, as a getter in vacuum tubes, as analloying agent in steel, in surgical appliances, photoflash bulbs,explosives, fiber spinnerets, and lamp filaments, and as asuperconductor (with niobium) to make superconductive magnets. As arefractory metal, Zirconium can be difficult to shape and work. However,a variety of Zirconium-aluminum and similar alloys may be quenched to anamorphous, ductile state. For example, see U.S. Pat. No. 5,980,652,describing amorphous Zr—Al alloys which have significant malleability intheir amorphous form. Such amorphous Zirconium alloys typically includealuminum, together with metals such as Fe, Co, Ni or Cu which promoteamorphous phase formation. Bulk glass-forming metals based on Ti, Al,Zir and/or Fe which can retain their amorphous state without extremelyfast cooling rates typically have three to five or more metalliccomponents with a large atomic-size mismatch to facilitate a highpacking density without crystallization. They generally form liquidmelts with a small free volume and high viscosity which areenergetically close to the crystalline state, because of their highpacking density and short-range order, which results in slowerecrystallization kinetics and improved glass forming ability [R. Busch,“The Thermophysical Properties of Bulk Metallic Glass-Forming Liquids”,JOM, 52 (7) (2000), pp. 39-42. A wide variety of Ti, Al, Zr, andFe-based glass-forming alloys, such as La—Al—Ni, Zr—Ni—Al—Cu, andZr—Ti—Cu—Ni—Be, exhibit very good bulk glass-forming ability with highthermal stability in the supercooled glass state, and low criticalcooling rates [A. Inoue, et al., Mater. Trans. JIM 31 (1991), p. 425; T.Zhang, et al., Mater. Trans. JIM, 32 (1991), p. 1005; A. Inoue et al.,Mater. Trans. JIM, 32 (1991), p. 609; A. Peker and W. L. Johnson, Appl.Phys. Lett., 63 (1993), p. 2342; all cited references incorporatedhereby reference]; Zr_(41.2)Ti_(13.8)Cu_(10.0)Ni_(12.5)Be_(22.5) (V1)has a very low critical cooling rate of about 1 K/s, which is 5-6 ordersof magnitude lower than some earlier metallic glass-forming systems. Thedifference in Gibbs free energy between an undercooled metal alloy glassand the corresponding crystallized alloy is the driving force forcrystallization. When it is low, as in bulk glass forming alloys,glass-forming ability is high as has been done for alloys such asZr—Ti—Cu—Ni—Be, and Cu—Ti—Zr—Ni. The Gibbs free energy difference forsuch “stable” glass-forming alloys may be only 2-4 Kilojoules per mole,normalized to the melting temperature of the respective alloy, even whencooled to temperatures as low as {fraction (1/3)} the crystallinemelting temperature of the alloy. The metal glass formers with thelowest critical cooling rates have smaller (e.g., less than 2 kJ/mole)Gibbs Free Energy differences than do the glass formers with highercritical cooling rates. The small driving force for crystallization ofsuch bulk metal glass mixtures results from their small free volume, andtheir short-range order in the supercooled liquid, because the varietyof atoms with different sizes in the mixture permits effective packingin the glassy state.

[0007] Amorphous alloys containing zirconium and titanium have excellentintrinsic corrosion resistance and mechanical properties, butunfortunately have been very expensive. Powder preparation for powdermetallurgy manufacturing is also very expensive.

[0008] Zirconium is not scarce in nature, but is expensive to extractand reduce from its ores, because of its very high reactivity and highmelting point. It is also difficult to purify magnesium chloridebyproduct, and even more expensive to prepare in powder or alloy formsuitable for advanced powder metallurgical manufacturing processes.Uniform alloy formation can also be an expensive processing step.Zirconiun occurs chiefly as a silicate in the mineral zircon (ZrSiO₄),and as an oxide in the mineral baddeleyite. Zirconium is producedcommercially by reduction of chloride with magnesium (the KrollProcess), as well as other methods. Hafnium is invariably found inZirconium ores, and the separation of Hf from Zr is difficult.Commercial-grade Zirconium accordingly contains from 1 to 3% Hafnium.

[0009] Efforts have been made to directly produce titanium powders byreduction of titanium halides in molten salts, and by ultrahightemperature plasma treatment of TiCl₄, but such approaches have not yetfound commercial success. Sodium fluorotitanate, Na₂TiF₆, dissolved inmolten cryolite, can be reduced by metallic aluminum to produce a powderof metallic Ti, but requires addition of NaF in stoichiometric amountduring the reaction to preserve the liquid cryolite medium, and produceslarge quantities of sodium fluoroaluminate byproduct.[3Na₂TiF₆+4Al+6NaF+3Ti, see J. Besida, et al., “The Chemical Basis of aNovel Fluoride Route to Metallic Titanium”]. Similarly, the AlbanyResearch Center (formerly the U.S. Bureau of Mines) has investigated thereduction of titanium tetrachloride in molten chloride salts, [S. J.Gerdemann, et. al., “Continuous Production of Titanium Powder”, at pp.49-56 in “Titanium Extraction and Processing”, Misra and Kipourous, ed.,ISBN 0-87339-380-5 (1996); J. C. White and L. L. Oden, “ContinuousProduction of Granular or Powder Ti, Zr, Hf or Other Alloy Powders”.U.S. Pat. No. 5,259,862,], but purity, separation, oxidation and otherissues may present difficulties. Plasma thermal reduction of titaniumchlorides is also a recent approach to producing titanium products, bututilizes heating to extremely high temperatures, and is accordingly veryenergy intensive.

[0010] Accordingly, there is a need for efficient, continuous processesto directly produce metals such as titanium and zirconium alloy powdersas commodity products, and it is an object of one aspect of the presentinvention to provide such processes.

[0011] There is also a need to produce powder metallurgy materials foruse in manufacturing reinforced intermetallic composite and amorphousmetallic products, and it is an object of one aspect of the presentdisclosure to provide such materials and processes for manufacturingthem.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a graph of the Gibbs free energy of an aluminummonochloride formation from aluminum and aluminum trichloride as afunction of temperature;

[0013]FIG. 2 is a plot of the molar functions, at equilibrium, as afunction of temperature, of various aluminum and titanium chloridespecies;

[0014]FIG. 3 is a graph of the Gibbs free energy of achloroaluminothermic reduction of titanium chlorides;

[0015]FIG. 4 is a plot of the molar functions, at equilibrium, as afunction of temperature at atmospheric pressure, of various aluminum andtitanium chloride species;

[0016]FIG. 5 is a process and equipment flow diagram of thechloroaluminothermic reduction of titanium chlorides to produce titaniumaluminides;

[0017]FIG. 6 is a plot of the molar fractions of various aluminum andiron chloride and oxide species in the chloroaluminothermic reduction offerrous oxide, which may be applied to produce iron aluminide andalumina in powder form for powder metallurgy use; and

[0018]FIG. 7 is a process and equipment flow diagram of thechloraluminothermic reduction of zirconium chloride to produce zirconiumaluminides, together with the refining of titanium as titanium chloridesfrom its ore.

SUMMARY OF THE INVENTION

[0019] The present invention is directed to vapor-phase processes forproducing titanium and zirconium metals such as titanium and zirconiumaluminides (e.g., TiAl, Ti₃Al, ZrAl) high-performance alloys (e.g.,Ti—Al—V) and glass-forming metal alloys such as Zr—Ti—Cu—Ni—Al-basedalloys. Preferred aspects of the methods may comprise the steps ofgenerating a stream of aluminum subchloride at a temperature greaterthan about 1000° C. by contacting aluminum trichloride vapor with analuminum metal-containing source preferably at a pressure in the rangeof from about 0.1 to about 1.5 atmosphere, mixing a titanium and/orzirconium chloride reactant with the aluminum subchloride gas to reducethe titanium and/or zirconium chloride reactant(s) to metallic titanium,or titanium or zirconium alloys and to form aluminum trichloride gas,and removing the aluminum trichloride gas from the metallic reactionproduct. In the processes, aluminum subchloride gas, preferably aluminummonochloride, AlCl(g), although some aluminum dichloride may also bepresent, is used as a vapor-phase reducing agent for titanium chloride(e.g., titanium or zirconium trichloride, or titanium or zirconiumtetrachloride) vapor, to produce a metallic titanium and/or zirconiumbased metal, such as titanium aluminide, zirconium aluminide or titaniumpowder, and aluminum trichloride vapor, AlCl₃(g). The aluminumsubchloride gas (e.g., AlCl) may be subsequently regenerated for reuse.In this regard, the aluminum trichloride to aluminum subchlorideconversion cycle is relatively inexpensive, and may utilize a relativelyimpure aluminum source, such as scrap aluminum or an inexpensivealuminum-silicon-iron alloy formed by carbothermic reduction of bauxite.The aluminum source is reacted with AlCl₃(g), for example, at about1200° C. at a pressure of 0.2 atmospheres, to form aluminum monochloridegas AlCl(g). A selected reaction material such as titanium or zirconiumtetrachloride or trichloride or mixtures thereof may be introduced into,or otherwise mixed with the aluminum monochloride gas to form a reactionmixture. On cooling of AlCl gas to a temperature at which aluminum (or atitanium or zirconium aluminide) and aluminum trichloride are morestable than the aluminum subchloride vapor, (e.g., cooling toward about600-700° C.), the aluminum monochloride is less stable and is more ableto serve as a reducing agent for the zirconium and/or titanium chloride,together with any other alloying metal chlorides. The temperatures atwhich the “oxidation” of AlCl to AlCl₃, and the “reduction” of titaniumchloride (and any other alloying agent and reactant) occurs to acommercially significant extent, depend upon the overall thermodynamicsof the particular reaction. It is an important benefit that the reducedtitanium or zirconium or titanium alloy reaction product may be producedin powder form. Coatings and solid deposits may also be provided. Unlikethe standard Kroll batch process for titanium manufacture, themanufacturing process can be continuous, and can be scaled forefficient, large-scale production.

[0020] The process can be utilized to produce intimately uniform,“molecularly mixed” titanium and/or zirconium aluminide powders (e.g.,TiAl, TiAl₃, ZrAl, ZrAl₃, etc.) or pure titanium powder without the needfor the expensive and energy-intensive arc refining required by thecurrent Kroll process. The process can also be adapted to incorporateother alloying agents such as niobium, to produce important titaniumalloys such as Ti—Al—Nb powders, and can also be applied to include TiB₂and other refractory materials of importance to powder metallurgical andthermal spray metallurgical manufacture. The AlCl vapor produced may bereacted directly with zirconium chloride introduced as a vapor, spray orpowder (ZrCl₄, ZrCl₃, etc.) to produce zirconium aluminides.

[0021] Unlike the standard Kroll batch process for Zirconium andtitanium manufacture, the zirconium manufacturing process is continuous,and can be scaled for efficient, large-scale production. The process isalso able to produce intimately uniform, “molecularly mixed” titaniumand zirconium alloys (e.g., ZrAl, ZrAl₃, etc.) without the need for theexpensive and energy-intensive arc refining required by the currentKroll process. The process can also be extended by subsequent treatmentwith hydrogen and zirconium chloride to produce “pure” Zr metal powdersfrom the alloys. The process is technically robust and can be adapted toincorporate a wide variety of alloying agents such as uranium, niobium,tin, iron, chromium and nickel, to produce a correspondingly widevariety of Zirconium alloys. The process can also be extended to processZirconium ores in energy and material-efficient recycle operation. Itmay also be used, if desired, to preferentially separate Hafnium underefficient energy conditions.

[0022] The invention is also directed to reaction apparatus formanufacturing zirconium alloy powder, and to the powder so produced.

[0023] As indicated, in various aspects, the present methods may be usedto produce a wide variety of intermetallic compounds such asintermetallic zirconium aluminides and titanides. Intermetallic alloysor compounds have an ordered periodic arrangement of the constituentelements, which provides a chemically bonded crystal structure ratherthan the solid solutions found in many conventional alloys. The methodsmay also be used to produce amorphous alloys.

DETAILED DESCRIPTION OF THE INVENTION

[0024] As indicated, the present disclosure is generally directed tocontinuous, vapor-phase process for direct manufacture of Ti, andtitanium and/or zirconium alloy powders. The methods are very robust,and in addition to titanium itself, are particularly desirable forproduction of intermetallic TiAl, Ti₃Al, TiAl₃, FeAl, NiAl₃, NiAl, ZrAl,ZrAl₃, Ni₃Al, glass-forming Ti and Zr alloys, and other alloys aspowders suitable for powder metallurgy fabrication. The process hasinherent economies suitable for making such titanium alloys asinexpensive, commodity metals for general use, rather than as exoticmaterials to only be used only when their high performance is requireddespite their presently high cost.

[0025] The present processes use an aluminum subchloride transportreaction. In this regard, with reference to specific titanium-basedembodiments, aluminum subchloride vapor is used to reduce titaniumtetrachloride vapor, to directly and efficiently produce TiAl, Ti₃Al,TiAl₃ or Ti powder. A variety of different Ti and Ti and/or Zr alloyproducts may be produced merely by varying the reaction stoichiometry:

For TiAl 7AlCl+2TiCl₄

2TiAl+5AlCl₃   (Eq. 1)

For Ti₃Al 15AlCl+6TiCl₄

2Ti₃Al+13 AlCl₃   (Eq. 2)

For TiAl₃ 13AlCl+2TiCl₄

2TiAl₃+7AlCl₃   (Eq. 3)

For Ti 2AlCl+TiCl₄

Ti+2AlCl₃   (Eq. 4)

[0026] As shown in FIG. 1, in the aluminum subchloride transportreaction, AlCl is produced by reacting aluminum trichloride atatmospheric pressure with crude aluminum at temperatures over about1200° C.:

Aluminum sub-chloride production 2Al(g)+AlCl₃(g)

3AlCl(g)   (Eq. 5)

[0027] As shown in FIG. 1, the Gibbs Free Energy of the formation ofaluminum monochloride from aluminum and aluminum trichloride isexothermic over about 1200° C., so that AlCl vapor can be readily formedabove this temperature.

[0028] This reaction has a negative-slope Gibbs Free Energy vs.temperature curve, so that upon cooling the AlCl gas, e.g., to atemperature of 500-700° C., the free energy becomes significantlypositive, aluminum is regenerated, and the vapor can become a reducingagent for the TiCl₄ component of a reaction mixture. FIG. 1 illustratesthe Gibbs free energy of the aluminum transport reaction of Eq. (5). Asshown in FIG. 1, two temperature ranges are illustrated in the reactionexample described here:

[0029] Subchloride generation T1 at about 500-600° C., at which aluminummetal is generated and condensed from the vapor phase to reduce TiCl₄gas, and

[0030] Reduction temperature T2 at about 1200-1300° C., at which AlCl isgenerated

[0031]FIG. 2 represents an equilibrium calculation (by Outukumpu HSCthermodynamic calculation software) of the molar concentration ofaluminum subchloride and aluminum trichloride species from the reactionof Eq. (5), at thermodynamic equilibrium, over a temperature range fromthe sublimation point of AlCl₃ at about 300° C., to about 2000° C. Atthe reduction temperature T1, aluminum metal is a predominantequilibrium species, and AlCl₃ vapor (which will remove the chlorinecomponents from the reactions of Eq. (1)-(3), is also a favored speciesat equilibrium conditions. At the subchloride generation temperature,T2, aluminum monochloride vapor is the predominant species atequilibrium, and AlCl₃ vapor is at relatively low concentration.

[0032] As indicated, the present methods can use AlCl vapor as a vaporphase reducing agent for titanium and/or zirconium chlorides, alone ormixed with other alloying or other materials. The reduction of TiCl₃ orTiCl₄ by AlCl is thermodynamically highly favored at temperatures in theT1 range of about 500-700° C., as shown by the graph of FIG. 3 for thereaction of TiCl₄ with AlCl, to produce TiAl powder.

[0033] The calculation of reaction product species concentration for thefunction of TiAl from TiCl₄ and AlCl according to Equation 5 atthermodynamic equilibrium (by Outukumpu HSC thermodynamic calculationsoftware) similarly shows a very favorable exothermic reaction at the T1temperature of 500-700° C. to form TiAl by the process withoutsubstantial formation of titanium subchlorides, which are more stable athigher temperatures. FIG. 4 shows the molar proportions of the reactantsand reaction products at the T1 reaction temperature of 500-700° C. Asindicated, the reaction will be further driven to completion by thereaction of Ti and Al to form TiAl, and by the separation of the metalparticles from the AlCl₃ reaction vapor, as will be more fully discussedin connection with FIG. 5. Even at elevated temperatures, for example,between 700° C. and 1100° C. where titanium subchlorides are relativelymore stable, these subchloride vapors can still be separated frommetallic solids.

[0034] Aluminum subchloride vapor can also be used to reduce Zirconiumtetrachloride vapor, to directly and efficiently produce ZrAl, Zr₂Al₃,ZrAl₃, Zr₃Al or similar alloy powders. The different Zr alloy productsmay be produced merely by varying the reaction stoichiometry:

For ZrAl 7AlCl+2ZrCl₄

2 ZrAl+5AlCl₃   (Eq. 6)

For Zr₂Al₃ 17AlCl+4ZrCl₄

2 Zr₂Al₃+11AlCl₃   (Eq. 7)

For ZrAl₃ 13AlCl+2ZiCl₄

2ZrAl₃+7AlCl₃   (Eq. 8)

[0035] As indicated, the methods and apparatus of the present inventionuse AlCl vapor as a vapor phase reducing agent for Zirconiumtetrachloride, ZrCl₄. FIG. 3 is a graph of the Gibbs free energiescalculated by F*A*C*T software of the ZrCl₄, HFCl₄ and UCl₄ reductionreactions with AlCl, and the reaction of Al with ZrCl₄. As shown bycurves 1-3 of FIG. 3, AlCl vapor has sufficient “reducing power” toreduce highly reactive ZrCl₄, as well as HfCl₄, and UCl₄ which are evensomewhat more difficult to reduce. However, as shown by curve 4 of FIG.3 (4Al+3 ZrCl₄

3Zr+4 AlCl₃), the reduction of ZrCl₄ by aluminum to directly form pureZirconium metal is not favored thermodynamically. Accordingly, AlClvapor cannot be used directly to produce pure Zr metal from ZrCl₄ at theT1 temperature, because Aluminum metal will be produced, rather than Zrmetal. Fortunately, however, Zirconium forms a wide variety of alloyswith aluminum and other metals. Many of these alloys are stronglyexothermic in their heats of formation, as shown by the following Table:Alloy ΔH (eV/atom) ΔH (Joules)* ΔG (Joules) Zr₃Al −0.3  ***** ***** UAl₃***** −114,215** −114,482 Zr₄Al₃ −0.425 ***** ***** ZrAl −0.45 −135,000(estimated) −9,000(estimated) TiAl₃ −0.475 −142,255 −135,948ZrAl₃ −0.5  −150,000(estimated) 143,000(estimated) Zr₂Al₃ −0.525 **********

[0036] Because of the high heat of formation of a wide range ofZirconium-aluminum alloys, the formation of these Zr—Al alloys by directreduction with AlCl is thermodynamically favored at temperatures in theT1 range of about 500-700° C. A calculation of Zr, Al and Cl reactionproduct species at thermodynamic equilibrium (calculated by OutukumpuHSC thermodynamic calculation software, substituting the values of TiAl₃for ZrAl, which are similar, see the table above; the same results forZrAl₃, etc.) shows a very favorable reaction at the T1 temperature of500-700° C. to form ZrAl and related Zr—Al alloys/compounds. Thefollowing FIG. 4 shows the molar proportions of the reaction products of7AlCl+2ZrCl₄, (Eq. 1, above) with emphasis by red line for theproportions of the various species at the T1 reaction temperature of500-800° C. As shown in FIG. 4, the desired products, ZrAl powder, andAlCl₃ gas, are by far the predominant products of the reaction at 700°C. The reaction can be further driven to completion by phase factors,which permit the separation of the Zirconium-aluminum alloy particlesfrom the AlCl₃ reaction vapor, and any small amounts of subchlorideproduced.

[0037] While a method has been discussed for the production ofintermetallic TiAl, the stoichiometric ratio of the TiCl₄ and AlClreactants can be readily changed to produce other alloys, such as Ti₃Alor TiAl₃ intermetallics, or Ti metal, in accordance with the previousreaction equations, Eq. 1-4. Reactants such as boron, niobium, iron,nickel, and/or chromium chlorides may also be included with the TiCl₄,to make high-performance alloys such as Ti-48Al-2Nb-2Cr, and Ti₂AlNb,which are inexpensive and highly uniform because their precursorchlorides are mixed in the vapor phase. Such chlorides may at leastpartially dissolve in titanium tetrachloride, so that even if they arenot volatilized at the reduction reaction temperature range T2, theywill be intimately dispensed when sprayed with the TiCl₄ into thereaction zone. To the extent such chlorides so not dissolve in the TiCl₄to provide dispersed levels in the final metallic titanium-basedproduct, they may also be finely ground and dispersed in a TiCl₄ liquidwhich is sprayed into the reduction reaction zone. Oxides of thesealloying materials may also be used, and the resulting reaction productwill contain alumina powder, which may be separated using densityclassification techniques, or my be retained as a ceramic reinforcingagent.

[0038] Titanium and titanium alloys are used as structural components inmany aircraft, space satellites and missiles. Typical applicationsinclude Ti fan disks, turbine blades, and vanes in aircraft turbineengines, and cast and forged structures. Unalloyed titanium is used injet engine shrouds, cases, airframe skins, firewalls, and other hot-areaequipment for aircraft and missiles; and is also used inheat-exchangers, while alloys such as Ti-6Al-2Sn-4Zr-2Mo (Ti-6242, orUNS 54620) are used in gas turbine engine and air-frame applicationswhere high strength and toughness, creep resistance, and hightemperature stability at temperatures up to 450° C. (840° F.) arerequired. Such alloys can be made in powder form by incorporating SrCl₂,ZrCl₂, and MoCl₂ in the TiCl₄.

[0039] The present glassy alloy production process is highly energyefficient and robust, and has low energy consumption and capitalinvestment. In the process, aluminum subchloride vapor is used to reducemixed metal chloride vapor, to directly and efficiently produceamorphous metal alloy powders. A wide variety of different metal glassalloy products may be produced, merely by varying the reactionstoichiometry. For example, to make crystalline or bulk glass alloyssuch as Zr_(52.5)Cu_(17.5)Ni_(14.5)Al₁₀Ti₅ (10K/sec critical coolingrate) or Zr₅₇Cu_(15.4)Ni_(12.6)Al₁₀Nb₅ (10K/sec critical cooling rate),the following chloride vapor in appropriate stoichiometry would beblended for reaction with AlCl(g) to form the desired glass composition.

[0040] ΔG@600° C.

For ZrAl component 7AlCl(g)+2ZrCl₄

2ZrAl+5AlCl₃(g)−130 kJ   (Eq. 6)

For Ti component 2AlCl(g)+TiCl₄

Ti+2AlCl₃(g)−239 kJ   (Eq. 9)

For Cu component AlCl(g)+CuCl₂

Cu+AlCl₃(g)−321 kJ   (Eq. 10)

For Nb component 5AlCl(g)+2NbCl₅

2Nb+5AlCl₃(g)−998 kJ   (Eq. 11)

For Ni component AlCl(g)+NiCl₂

2Ni+5AlCl₃−308 kJ   (Eq. 12)

For Fe component 2FeCl₃+3AlCl(g)

2Fe+3AlCl₃−773 kJ   (Eq. 13)

[0041] Other metal chlorides, such as volatile tungsten chlorides, WCl₄and WCl₅, can also be easily reduced by AlCl(g) at 600° C. to includesmall amounts (e.g., 0.1-2% by weight) of this relatively large metal inthe alloy composition.

For W component 5AlCl(g)+2WCl₅

2W+5AlCl₃−1568 kJ   (Eq. 14)

[0042] For ZrAl manufacture (Eq. 6) and the inclusion of Zr inglass-forming alloys, the effective equilibrium curve is similar to thatof FIG. 4 for TiAl (Eq. 1).

[0043] As indicated, the present methods will reduce other metalchloride mixtures with titanium and or zirconium chlorides. Chloridessuch as NiCl₂, NbCl₅ and FeCl₃ can be directly reduced by AlCl vapor,because the Gibbs Free Energy for their direct reduction (particularlyto form alloys) is negative. Substantially all transition and rare earthmetal chlorides can similarly be reduced by aluminum to form intimatelymixed metal powders. Fe, Nb, Ni, Co, Cu and similar metals are easilyreduced by aluminum, so crystalline and amorphous alloys containingmixtures of all of those materials can be made. AlCl(g) can even reducerefractory ZrCl₄. AlCl vapor cannot be used to directly produce pure Zrmetal from ZrCl₄, because the Gibbs Free Energy for this reaction ispositive in the 500-1000° C. range. Fortunately, however, zirconium isstrongly exothermic in forming alloys with aluminum, and a variety ofglass-forming metals. This has important implications for themanufacture of inexpensive Zr-containing bulk amorphous metal powders.Because the Gibbs Free Energy of properly formulated zirconium-aluminumbulk metal glasses only differs from that of the precipitatedcrystalline alloys by about 2 kJ/g-atom, which is a very small amount,the reduction by AlCl(g) of the glass alloys including zirconium metalis still thermodynamically favorable. Thus, glassy zirconium alloyformation by AlCl(g) reduction is thermodynamically favorable atreduction temperatures of less than 900° C. (e.g., 500-700° C.) becauseof the high heat of formation of zirconium-containing glassy alloys.ZrAl powder, and AlCl₃ gas, are by far the predominant products of thereaction at 700° C. The reaction is further driven to completion byphase factors, which easily permit the physical separation of theamorphous metal alloy particles from the AlCl₃ reaction vapor and anysmall amounts of subchloride produced.

[0044] A preferred example of the overall process manufacturing TiAl isillustrated in the flow diagram of FIG. 5. As shown in the flow diagram,scrap or crude aluminum 50 and aluminum trichloride 52 are reacted in aretort tower 54 at the reaction zone T2 temperature of 1200-1300° C., toproduce AlCl gas 56, which is conducted to a separate reaction reactor58 for reduction of TiCl₄ at the T1 reaction reactor temperature of 700°C. and 1500° C. Aluminum trichloride may be introduced as a vapor intoan aluminum melt, and the aluminum melt may be “splashed” or circulatedthrough the tower in order to increase reaction kinetics. The interiorsurfaces of the tower 54 should be constructed of materials such ascarbon, spinels, alumina, tungsten, or even titanium or zirconium (whichmay be conveniently thermally sprayed on interior surfaces of thereaction vessels and conduits) or other such refractory materials whichare relatively inert to reaction with aluminum and aluminum chlorides atelevated temperatures. Titanium tetrachloride 60 is mixed with the AlClgas 56 in the T1 reaction zone 58, and the reaction mixture is cooled toa temperature of about 500-700° C. Relatively cool liquid TiCl₄(molecular weight 189.7) may be sprayed into the hot AlCl gas (molecularweight 62.4) to both partially cool it and vaporize the TiCl₄ (note thatthe reaction is exothermic, in any event). Heat may be recovered forpower generation heating of aluminum and/or aluminum trichloride fromthe reactor 58.

[0045] In the appropriate temperature range, the vapor-phase AlCl is areducing agent for the TiCl₄ blended therewith, as previously discussed,to produce TiAl powder 62, and vapor-phase AlCl₃ gas 64. The solid TiAlpowder 62 produced by the reaction may be easily separated from thealuminum trichloride vapor by a cyclone 66 or other separation systemoperating above the vapor point of AlCl₃. The powder 62 may be flushedwith an inert gas such as argon, or a reversibly removable gas such ashydrogen (which can alloy with the zirconium and/or titanium metalpowder at lower temperatures), to assist flushing and removal of anyresidual AlCl₃. Vacuum treatment of the collected TiAl product even atmoderate temperatures, such as in the range of 100° C. to 400° C.(preferably 100-350° C.) may also be used to further remove any residualchloride components. A chloride source such as TiCl₄ or ZrCl₄ may beused with hydrogen at these low temperatures to remove aluminum fromaluminum containing alloys, leaving pure titanium or zirconium. Thehydrogen respectively forms Ti or Zr hydrides, which release thealuminum for removal as AlCl vapors. If desired, as shown in FIG. 5,TiAl powder may be at least partially recycled to the reactor 58 toserve as a nucleating source for metal deposition, if it is desired toincrease the particle size of the TiAl or other metal powder produced bysuch reaction processes.

[0046] It should be noted that the process equipment is relativelysimple and inexpensive, consistent with commodity production, ascompared to conventional titanium batch production equipment (closedsteel retorts, vacuum arc equipment, etc.). and can be easily scaled forlarge capacity. Conventional metal chloride tower, piping, and powderseparation cyclone equipment, none of which are particularly expensive,may constitute the principal components.

[0047] The present process utilizes close coupling of distillationseparation, and chemical vapor reaction systems, to improve the yieldsof the reaction, the production of desired alloys, and to lower energyconsumption and capital investment. Energy savings can be realized, forexample, when a crude carbothermic molten aluminum such as a mixture ofaluminum and aluminum carbide or Al—Fe—Si alloy, and heated aluminumtrichloride from specific reaction steps are separated and used asreactants in a zirconium or titanium reduction, and TiCl₄ or ZrCl₄generation steps. The energy from the latent heat and exothermicreactions may be used to drive other reactions. The process is veryrobust, and produces alloys as powders suitable for powder metallurgyfabrication, and for preparation of titanium and/or zirconium-aluminumalloys. The process has inherent economies suitable for making suchtitanium and/or zirconium alloys as inexpensive, commodity metals forgeneral use, rather than as exotic materials to be used only when theirhigh performance is required despite their presently high cost. It mayalso be used to prepare Zr metal powder from the Zr—Al alloy bytreatment with hydrogen and a chloride source such as ZrCl₄.

[0048] The aluminum trichloride byproduct, can also be used to directlyrecover titanium, zirconium, and other metals directly from their ores.An example of the overall process is further illustrated in the flowdiagram of FIG. 7. As shows in FIG. 7, scrap aluminum or evenless-expensive carbothermic aluminum (e.g., a mixture of molden aluminumwith aluminum chloride) or crude coke-furnace reduced Al—Fe—Si, arereacted with aluminum trichloride in a reaction tower at the reactionzone T2 temperature of 1300-1500° C., to produce AlCl vapor. Thefurnaced crude aluminum can be introduced into the tower at hightemperature (e.g., 1500-2200° C.), and this heat can be used directly inthe formation of AlCl. The aluminum subchloride gas is conducted to aseparate reaction zone for reduction of a glassy metal chloride mixtureat the T1 temperature. Glassy metal-forming components such as FeCl₃,TiCl₄, NbCl₅, NiCl₂ and/or ZrCl₄, as well as WCl₅, may be mixed with theAlCl gas in the T1 reaction zone, and the reaction mixture cooled to atemperature of about 500-800° C. TiCl₄ and ZrCl₄, and powderednon-volatilized chlorides such as CuCl₂ may be used to cool the hot AlClgas and vaporize the chlorides. Expansion through a nozzle into apartial vacuum zone can also be used to very rapidly cool the reactingchloride vapor. A partial vacuum to produce a subatmospheric pressure inthe AlCl generator (e.g., 0.1 to 0.9 atmospheres) is also beneficial forthe AlCl formation. A partial vacuum is relatively easy to implement forthe methods described herein, because the aluminum chloride byproductcondenses to a solid at temperatures below about 200° C.

[0049] Thus, the reactant vapors may be initially mixed at a temperatureabove the crystallization/solidification temperature of the metal alloy(which is typically a deep eutectic with a relatively low meltingpoint), and rapidly cooled to a temperature below the glass transitiontemperature of the alloy.

[0050] In the T1 reaction zone, the aluminum subchloride vapor, AlCl(g)vapor becomes a reducing agent for the Ti or Zr alloy, or glassy metalchloride mixture as previously discussed, to produce crystalline orglassy alloy powder as described by reactant formulation selection, andAlCl₃ vapor. The solid alloy powder produced by the reaction may beeasily separated from the aluminum trichloride vapor by a cyclone orother separation system operating above the vapor point of AlCl₃. Theseparated crystalline or amorphous alloy powder may be flushed with aninert gas such as argon or hydrogen to assist removal of any residualAlCl₃. Small amounts of subchlorides which may be produced, are alsorelatively volatile at the recovery temperature, and can be removed withthe AlCl₃. Hydrogen can be used to further remove residual chlorides asaluminum trichloride vapor at 100-300° C., preferably at subatmosphericpressure.

[0051] The ordering of these glass alloy metals of different atomic sizeinto crystalline structures has low driving force and takes significanttime, particularly if the composition has a low (1-3 kJ/mole) differencein Gibbs Free Energy between the glass and alloy states. The reductionof the mixed metal chloride vapor by aluminum can be sufficiently rapidthat the glassy alloys do not have time to crystallize. If an adiabaticor other expansion nozzle is used to cool the reactants, cooling canoccur at extremely high rates, of up to 10⁶ degrees K per second.

[0052] An example of the overall process and a reaction system forcarrying it out is further illustrated in the flow diagram of FIG. 5. Asshown in FIG. 5, scrap aluminum or even less-expensive carbothermicaluminum or crude coke-furnace reduced Al—Fe—Si, are reacted withaluminum trichloride in a distillation reaction tower at the reactionzone T2 temperature of 1200-2000° C., to produce AlCl vapor. Ifcarbothermic aluminum is used, the heat of the latest molten metal isused efficiently in the aluminum subchloride manufacture. This reactivedistillation also retains most other metals or metal chlorides in thereactive distillation tower, because of their lack of volatility. Thesemetals and/or chlorides are in solid, non-aqueous form which permitsready reuse. The pure aluminum subchloride gas is conducted to aseparate reaction zone for reduction of ZrCl₄ at the T1 temperature.ZrCl₄ is mixed with the AlCl gas in the T1 reaction zone, and thereaction mixture is cooled to a temperature of about 500-700° C. ZrCl₄(molecular weight about 233) may be used to cool the hot AlCl gas(molecular weight about 62.4), and vaporize the ZrCl₄. In the T1reaction zone, the aluminum subchloride vapor, AlCl(g) becomes areducing agent for the ZrCl₄ as previously discussed, to produce ZrAl orother Zr-aluminide alloy powder by stoichiometry control, and AlCl₃ gas.The solid ZrAl alloy powder produced by the reaction may be easilyseparated from the aluminum trichloride vapor by a cyclone or otherseparation system operating above the vapor point of AlCl₃. Theseparated alloy powder may be flushed with an inert gas such as argon orhydrogen (which can alloy with the powder at lower temperatures) toassist flushing of any residual AlCl₃. Small amounts of subchlorides,which may be produced are also volatile at the recovery temperature, andcan be removed with the AlCl₃. It is also important that a zirconiumalloy coating can be deposited on substrates placed in the reductionzone. The substrates may be refractory substrates such as ceramic fibersor monofilaments such as silicon carbide fibers or tow, glass fibers,other metals such as uranium or uranium oxide cylinders or sphericalparticles steel or stainless steel fibers or reinforcing bars, conduitsor other structural members at a suitable temperature in the range of,for example, 300-1500° C. The substrates may be coated in the reactionchamber in any suitable manner, such as by placing them in the reductionchamber, moving them through the zone (e.g., filaments) or utilizing avibrating or fluidized bed with the reacting vapors. Continuousprocesses are particularly efficient, and benefit from the presentinvention. Any zirconium alloy powder may continue to be collected whichdoes not deposit on the substrates.

[0053] As shown in FIG. 7, hot AlCl₃ vapor produced by the reduction ofthe metal chloride mixture can be recycled to regenerate the AlCl vapor.Equally important the hot AlCl₃ vapor can be used directly in acountercurrent distillation reactor to generate the metal chloridevapors directly from ores such as Ilmenite (FeTiO₃) and Zircon (ZrSiO₄).Direct distillation and purification of ZrCl₄, TiCl₄, CoCl₂, NiCl₂,MnCl₂ and other volatile metal chlorides can be carried out from theirores using AlCl₃ vapor byproduct. This can eliminate the costly chemicalrefining steps which make Ti and Zr so expensive. Other ores ofconstituent transition or rare earth metals can be similarly extractedwith AlCl₃. Separation of minor chloride “impurities” is unnecessary ifthey are constituents of the metal alloy. The so-called “chloridereaction potential” which exploits the difference between the Gibbs FreeEnergy for metal oxides and metal chlorides, is used conventionally inmetal chloride production towers to separate different volatilechlorides, such as SiCl₄, TiCl₄ and FeCl₃. (See, for example, U.S. Pat.No. 4,288,411, “Process For The Selective Production Of An IndividualPlurality Of Pure Halides And/Or Halide Mixtures From A Mixture Of SolidOxides”. Because of the different “chloride reaction potentials of theIlmenite and Zircon ore constituents, the ore can be reacted with AlCl₃at elevated temperature to separate or remove different constituents oftheir ores, as shown at the right-hand side of FIG. 7. Because the AlCl₃vapor is already heated, this is a very energy efficient process. Asshown in FIG. 5, the hot AlCl₃ vapor produced by the reduction of ZrCl₄can be recycled to the first reactive distillation tower to regeneratethe AlCl vapor. Also, the hot AlCl₃ vapor can be used in acountercurrent or other distillation reactor to generate ZrCl₄ from oressuch as ZrSiO₄ (see, for example, Othmer, et al., “Halogen Affinities—ANew Ordering of Metals to Accomplish Difficult Separation”), AICKEJournal (Vol. 18, No. 1) January 1972, pp.217-220) to separate thedifferent constituents of the ore, as shown at the right-hand side ofFIG. 7, above. Given the difference in “chloride reaction potential”between HfCl₄ and ZrCl₄ as shown in FIG. 6, the HfCl₄ impurity can alsopreferentially be separated from the desired ZrCl₄ product, if suchseparation is desired.

[0054] As also shown in FIG. 7, a suitable zirconium ore may beprocessed in a counter-current manner to efficiently recycle the hotAlCl₃ vapor in ore processing and component extraction. A suitablezirconium ore such as Zircon (ZrSiO₄) or zirconium oxide ore such asbaddeleyite (ZrO₂) is introduced into a counter current reactor. Whilethe reaction is shown as a chloride reaction tower, through which theore passes downward, in practice a series of interconnected metalchloride reactors may be used, in which the vapor flows may becontrolled among them to simulate counter current processing, may alsobe used. The reactive AlCl₃ vapor is introduced at the “bottom” of thecolumn (or to the rector with the last-processed ore components), whichcontains the “lowest chloride potential” of the potentially volatilechloride cations (e.g., SiCl₄) and the previously reacted nonvolatilechloride component of the ore (e.g., CaCl₂ NaCl), the other volatilecomponent having been conducted upwards as chloride vapors, as shown inFIG. 7. SiCl₄ and enriched HfCl₄ may be removed, distilled andprocessed. ZrCl₄ may similarly be recovered and distilled, if desired,while iron chlorides and other chloride reactive metals with a highchloride potential may also be recovered at appropriate temperaturesalong the reactor. The same result can be achieved with titanium oressuch as ilmenite and rutile.

[0055] While the reaction has been discussed for the production of ZrAl(77% Zr by weight), the stoichiometric ratio of the ZrCl₄ and AlClreactants can be changed to produce other alloys, ranging from Zr₃Al toZrAl₃. Provided the high heat of formation of the respective alloy isretained, other reactants such as Boron, Niobium, Iron, Nickel, Tinand/or Chromium chlorides may also be included with the ZrCl₄, to makehigh-performance alloys, which are inexpensive and may be highly uniformif their precursor chlorides are mixed in the vapor phase. Uraniumalloys with aluminum can be produced in the same way, as well as Zr—Ualloys.

[0056] Carbon-generating gases, such as aromatics and alkanes (e.g.,C₂H₂ or benzene or CH₄) and halide-substituted aromatics and alkanes(e.g., CCl₄ or C₆Cl₆) may also be included to produced zirconium orother carbide components:

CCl₄+AlCl)

C=2AlCl₃ (ΔG=838 kilojoules at 1000° Kelvin)

Zr+4C=

ZrC₄ (ΔG=183 kilojoules at 1000° Kelvin)

Ti+C

TiC (ΔG=173 kilojoules at 1000° Kelvin)

[0057] Fibers or surfaces of carbon organopolymers such as polyvinylchloride or polyvinylidine chloride may be “coated” with zirconiumcarbide in the reduction reaction zone, when in contact with thereacting aluminum subhalide and zirconium halide vapors.

[0058] Aluminum may also be at least partially removed from the Zr—Alalloy powders, by reactively distilling them with AlCl₃ at a T2temperature of 1600-1800° C. or more where AlCl and AlCl₂ vapor have avery negative Gibbs Free Energy:

ZrAl+AlCl₃

Zr+AlCl(vapor)+AlCl₂(vapor)

[0059] This secondary distillation can also be used to preferentiallyremove Hf as Hf chlorides, because of the higher Gibbs Free Energy ofthe Hafnium compounds compared to Zr Chlorides, leaving enriched Zrmetal powder, reduced in Hf.

[0060] The process uses very simple, scalable and inexpensive equipmentand unit operations. The process is very efficient in thermal energyutilization and material reuse and can be easily scaled for largecapacity. Conventional metal chloride manufacturing towers, piping, andpowder separation cyclone, none of which are particularly expensive,constitute the principal components. Aluminum raw material can be veryinexpensively produced in molten form using a conventional stack-type orsimilar carbothermic reduction furnace (see, for example, Alcoa'sexpired U.S. Pat. Nos. 4,299,619 and 3,971,653 to Alcoa, entitled,“Energy Efficient Production Of Aluminum By Carbothermic Reduction ofAlumina”).

[0061] The apparatus and process can have relatively low operatingcosts. The aluminum used in the process may be inexpensive scrap,aluminum carbide or crude raw aluminum such as Al or Al—Fe—Si producedat very low cost by carbothermic reduction of bauxite, which can bedelivered “hot” in molten form at 1300-1800° C. for reactivedistillation with AlCl₃ to produce AlCl. Carbothermic production ofmolten Aluminum directly uses the latent heat energy of the moltenaluminum for the AlCl vapor production. If aluminum scrap is used, thevaluable alloy components of the scrap can generally be separated andrecovered by the reactive distillation in the formation of volatileAlCl, as another ecological and economic benefit of the process. Inaddition, even Zirconium aluminides (such as ZrAl₃ and ZrAl scrap orproduct for rework) can be used as an aluminum source for AlCl vaporproduction (albeit at relatively high temperatures), with the addedbenefit of producing a higher Zirconium content, as discussed above, for“pure” unalloyed Zr production.

[0062] The previous description has used chlorine as the halidecomponent. Other halides may also be used, but are considerably moreexpensive.

[0063] The processes of FIG. 7 use relatively simple and inexpensiveequipment and unit operations. Except for the AlCl vapor production, theprocess is a net producer of thermal energy, which can be recovered orotherwise utilized by appropriate thermal management.

[0064] An aluminum-wire or aluminum powder plasma gun to process AlCl₃for AlCl production or for introducing low-volatility metal chloridereactants may also be used.

[0065] Such methods for producing powdered metallic products cancomprise the steps of forming a stream of aluminum subchloride vapor ata temperature of at least about 1000° C., and preferably at least about1100° C. A suitable oxide or halide reactant is mixed with the aluminumsubchloride vapor stream. For example, the aluminum subchloride is thenreacted with the metallic oxide or halide reactant, to reduce thereactant to form a solid powdered metallic product and to form aluminumtrichloride vapor. The aluminum trichloride vapor can then be separatedfrom the powdered solid metallic product. Simple cyclone or gravityseparation are effective separation techniques, but filters, etc. mayalso be used.

[0066] For example, intermetallic iron aluminides and iron titanides maybe produced by reacting iron chlorides with aluminum subchloride in amanufacturing system like that of FIG. 5.

[0067]FIG. 6 illustrates an outukumpu thermodynamic equilibriumcalculation for the initial reactants 6FeO+16AlCl, calculated in termsof Fe and Al production. A slight excess of aluminum was included in thecalculation to show Fe and Al as separate curves. As shown in FIG. 6,the reduction reaction of FeO and AlCl proceeds readily at temperaturesbelow about 1200° C. In addition, the exothermic reaction of Fe and Alto form FeAl intermetallic compounds further drives the reaction tocompletion, to form FeAl powders.

[0068] When the iron or other metal chloride does not readily vaporizeat the reaction temperatures, it may be finely ground (e.g., to aparticle size of less than 44 microns, preferably less than 10 micronsin maximum dimension) and introduced into the aluminum subchloride as apowder, or with a carrier such as TiCl₄. Similarly, metal oxides such asFeO, NiO, or CoO may be finely ground and utilized as a reactant feedstream into the aluminum subchloride vapor in the reactor system of FIG.5, either alone or with a carrier reactant such as TiCl₄:

6FeO+15AlCl

6 FeAl+2Al₂O₃+15AlCl₃

[0069] This produces an iron aluminide intermetallic powder with about17% of an integral alumina powder reinforcement, which is ideal forpowder metallurgical manufacture of reinforced FeAl composites.

[0070] Similarly, FeTi powder may be produced by reducing FeO andtitanium chlorides with AlCl in the reaction zone 58 of a system likethat of FIG. 5:

6FeO+12AlCl+6TiCl₄

6FeTi+2Al₂O₃+12AlCl₃

)

[0071] This produces an iron—titanium intermetallic alloy powder withabout 15% integral alumina powder reinforcement, which is suitable forpowder metallurgical manufacture of FeTi-ceramic composites.

[0072] Having described the present invention with respect to variousspecific embodiments, it will be appreciated that a variety ofmodifications and adaptations may be made which are within the spiritand scope of the present invention.

What is claimed is:
 1. A method for producing titanium, or zirconium ortitanium aluminides comprising the steps of: forming a stream ofaluminum subchloride vapor; mixing a titanium chloride or zirconiumreactant or mixtures thereof with said aluminum subchloride vaporstream; reacting said aluminum subchloride vapor with the chloridereactant to reduce the chloride reactant to form a metallictitanium-based, zirconium-based or mixed titanium-zirconium-basedreaction product and to form aluminum trichloride vapor, and; separatingthe aluminum trichloride vapor from the solid metallic titanium-basedreaction product.
 2. A method in accordance with claim 1 wherein saidaluminum subchloride stream comprises at least 40 mole percent aluminummonochloride and is formed at a temperature of at least about 1100° C.and a pressure of at least 0.1 atmosphere, and wherein said reaction ofsaid aluminum subchloride and said titanium and/or zirconium chloride iscarried out at a temperature below about 1000° C.
 3. A method inaccordance with claim 2 wherein said titanium and/or zirconium chloridecomprises at least about 50 mole percent zirconium and titaniumtetrachloride or trichloride, and wherein said aluminum trichloridevapor is at least partially separated from said reaction product at atemperature of at least about 300° C.
 4. A method in accordance withclaim 3 wherein zirconium or titanium tetrachloride or trichlorideliquid or powder is vaporized by said aluminum subchloride vapor, to atleast partially cool the reaction mixture formed thereby to atemperature below about 900° C., and wherein an alloying agent such asniobium chloride, tin chloride, zirconium chloride and/or molybdenumchloride is mixed with said aluminum subchloride vapor together withsaid titanium chloride.
 5. A method for producing powdered metallicproducts comprising the steps of: forming a stream of aluminumsubchloride vapor at a temperature of at least about 1000° C.; mixing asuitable oxide or halide reactant with the aluminum subchloride vaporstream; reacting the aluminum subchloride with the metallic oxide orhalide reactant to reduce the reactant to form a solid metallic productand to form aluminum trichloride vapor, and; separating the aluminumtrichloride vapor from the solid metallic product.
 6. A method inaccordance with claim 5 wherein said reactant comprises finely dividediron oxide, cobalt oxide, nickle oxide, boron oxide or mixtures thereof,and wherein said metallic powder comprises aluminum oxide powdertogether with aluminum-based and/or titanium-based metallic powder.
 7. Amethod in accordance with claim 6 wherein said powdered FeO is mixedwith said aluminum subchloride vapor to form a mixture of powdered ironaluminide and aluminum oxide.
 8. A method in accordance with claim 6wherein titanium tetrachloride and an iron reactant selected from FeO,FeCl₂ and FeCl₃ or mixtures thereof, are mixed and reacted with saidaluminum subchloride vapor to form an iron titanium intermetallic alloypowder.
 9. A method in accordance with claim 8 wherein said ironreactant comprises at least 50 mole percent FeO, to produce anintermetallic iron titanium alloy and aluminum oxide powder.
 10. Amethod in accordance with claim 1 wherein said chloride reactantcomprises metal glass forming precursors in metallic glassstoichiometric ratio, and wherein said metallic reaction product is ametallic glass forming alloy.